Brown spots on young plant

Hi folks,

Just got back from xmas and my new seedlings (almost 2 weeks from germination) arn't looking that great. A lot are bordering on yellow but i think thats just my feed ring being to wide for such a young plant. One in particular though is looking very rough.



Two of its leaves (on the same node) have broken out with these nasty looking spots. They dont generally connect with the leaf edge, they also dont seem to overlap the veins (yet...). The leaves themselves are curled downward, I noticed they were doing this before I left 3 days ago. One other plant has a small cluster of similar looking spots on one leaf that was there 3 days ago but it hasn't gotten any worse.

Any thoughts? Really hoping its not fungus/insects

Some extra info -
- temps dont exceed 27 degrees celcius
- reservoir is 21 degrees celcius
- reservoir ppm is about 270
- lights are within the manufacturer stated optimum distance
- plants are in coco/perlite 70/30
- co2 is ~950ppm
- once a day watering

Iv been going thru something very similar and I thought it was bugs or a fungus from my soil but I think its a Manganese deficiency not to be mistaken with magnesium deficiency . I usually water with ph around the 6.2-6.5 mark so I tried lowering to 5.8-6ph and I have increased my nutrients, literally just watered them today that way. I also lowered my fan speeds I had them going pretty strong to shake off the bugs I thought were infecting the plant and the spots just kept going everywhere. Fingers crossed its not bugs but take a look at my journal on the last page I posted some leaf pictures and it looks identical to what you have. Your plant does seem to be over watered though, and are you feeding them anything?

I was going very easy on my nutes because I had a previous issue on another grow of too much nutrients but now I think these spots are a lack of nutes and ph being just a tad bit too high.

I've upped my nutes and i'm going to give them a foliar calmag spray. I wonder if supplementing co2 increases their nutrient needs?

Looking at the pictures here - https://www.royalqueenseeds.com/blog-manganese-deficiency-in-cannabis-plants-n577 - it doesn't look like my issue is Manganese. My spots are a light brown and clearly bordered where the pics show something more like dark blotches that blend to green.

Yes about nutes and co2

So before you go off adding everything you read it might need. You stated your PH going into the medium do you know what it's coming out as? If your PH is not stable ( in soil 6.3-6.8 is pretty safe) then no matter what you do will probably make it worse. Once your sure your PH is stable then diagnosing and treating the issues will become a lot easier but more than likely your plant will come around on it's own without having to do anything more. Another thing to remember when you spot a problem on your plant it's probably a week or more old as it takes time to show on the plant itself. The same goes for healing it will take time for the results of what you did to show so have some patience's and don't expect to see results over night.
Cheers!

I agree with most above except in coco you might see changes in 3 or so days.

Cal mag, gotta have it!

worldspawn said:

Hi folks,

Just got back from xmas and my new seedlings (almost 2 weeks from germination) arn't looking that great. A lot are bordering on yellow but i think thats just my feed ring being to wide for such a young plant. One in particular though is looking very rough.

View attachment 4255088

Two of its leaves (on the same node) have broken out with these nasty looking spots. They dont generally connect with the leaf edge, they also dont seem to overlap the veins (yet...). The leaves themselves are curled downward, I noticed they were doing this before I left 3 days ago. One other plant has a small cluster of similar looking spots on one leaf that was there 3 days ago but it hasn't gotten any worse.

Any thoughts? Really hoping its not fungus/insects

Some extra info -
- temps dont exceed 27 degrees celcius
- reservoir is 21 degrees celcius
- reservoir ppm is about 270
- lights are within the manufacturer stated optimum distance
- plants are in coco/perlite 70/30
- co2 is ~950ppm
- once a day watering

Click to expand...

Type of light and distance from the plant?

worldspawn said:

Hi folks,

Just got back from xmas and my new seedlings (almost 2 weeks from germination) arn't looking that great. A lot are bordering on yellow but i think thats just my feed ring being to wide for such a young plant. One in particular though is looking very rough.

View attachment 4255088

Two of its leaves (on the same node) have broken out with these nasty looking spots. They dont generally connect with the leaf edge, they also dont seem to overlap the veins (yet...). The leaves themselves are curled downward, I noticed they were doing this before I left 3 days ago. One other plant has a small cluster of similar looking spots on one leaf that was there 3 days ago but it hasn't gotten any worse.

Any thoughts? Really hoping its not fungus/insects

Some extra info -
- temps dont exceed 27 degrees celcius
- reservoir is 21 degrees celcius
- reservoir ppm is about 270
- lights are within the manufacturer stated optimum distance
- plants are in coco/perlite 70/30
- co2 is ~950ppm
- once a day watering

Click to expand...

Imo. Old leaves that are burned from an intense new light type/cycle/distance. Nothing to worry about.

Yeah good point Weedzen, I made a new reservoir (a bit stronger at 375ppm). I set the ph to 5.6 and ran the pump for a while, i was getting 6.1 but have only been able to get it down to 6 so far (in the run off). Its fighting me! I'll have another go tomorrow.

My nutes are designed for coco, i shouldn't need additional cal mag.

Lights are HLG 550's. ~55 centimetres away.

Thanks folks, will check back in a few days.

You don't mention your water... If your using RO, spring or distilled. YOU MUST ADD CAL/MAG. What ever C is in your feed, the coco has first dibs on it. Plant eats it up second. If your using RO, adjust the TDS to 250 with the C/M, THEN ad your base nutrients. I seem to have less issues in coco if I pH at 6.0
This guy really has some good coco management info... Give it a look.
https://cocoforcannabis.com/

Hi Jypsy Dog.

Jypsy Dog said:

You don't mention your water... If your using RO, spring or distilled.

Click to expand...

Its good old tap water, the ppm is 27. 250 of just cal/mag sounds a bit extreme Is this something you've tried yourself?

Jypsy Dog said:

This guy really has some good coco management info... Give it a look.

Click to expand...

Will do, thanks.

I'm pretty sure (now) I've just been too lax on the Ph, havent grown for a year so I'm making dumb mistakes; didn't buffer my coco/perlite initially, first watering wasn't Ph'd (was 6.2). Now i'm paying the price.

With the Cal/Mag in RO the target is 250/300 ppm. Get your shit back in line and she'll bounce right back. My seedlings get nothing but Cal/mag and root enhancer for the first 2 weeks, unless they show trouble. Good luck with the rest of the grow. Try 6.0 for a bit, seems to help me..

Raise your lights to about 30". About 75 cm

Heres the same plant now!



Crisis over! Thanks all. Treatment involved really pushing the coco ph down to under 6, lights went up about 4cm and I used a cal mag foliar spray (1ml/to 1lt) ph'd to 5.8. I can still see they are thirsting for more nitrogen, little flecks of yellow are on a lot of the plants. When the shops open I'm going to get a big tank and change to run-to-waste.

Initial causes for issue were laziness and ignorance Also the very wide halo feeder probably wasn't the best thing for a new plant with a narrow root spread.

Jypsy Dog said:

With the Cal/Mag in RO the target is 250/300 ppm. Get your shit back in line and she'll bounce right back. My seedlings get nothing but Cal/mag and root enhancer for the first 2 weeks, unless they show trouble. Good luck with the rest of the grow. Try 6.0 for a bit, seems to help me..

Click to expand...

I'm jackpot lucky, my city's tap water runs 250 and they use chlorine. So I don't even have to mix food for my seedlings just give them tap water. I'm in coco/perlite and shoot for a 5.5 to 5.8 pH.